February 5, 2014

Stranded Whales Lead Scientists To Discovery Of A New Species

Scientists have discovered a new whale species that lives in the deep ocean waters beyond the edge of the continental shelf.

Researchers, publishing a paper in the journal Marine Mammal Science, say they discovered Mesoplodon hotaula after studying seven animals stranded on remote tropical islands in the Indian and Pacific Oceans. The first specimen was a female found on a beach in Sri Lanka more than 50 years ago.

M. hotaula are part of the beaked whale family, which is a group of toothed whales distantly related to sperm whales, and their finding gives one scientist his discovery back.

"They are rarely seen at sea due to their elusive habits, long dive capacity and apparent low abundance for some species. Understandably, most people have never heard of them," Dr Merel Dalebout, an international team leader and visiting research fellow at University of New South Wales, said in a statement.

Paulus Deraniyagala, the director of the National Museums of Ceylon 50-years-ago, first described this species in 1963 when a blue-grey beaked whale washed up at Ratmalana near Colombo. However, two years later, other researchers ended up reclassifying this specimen as an existing species known as Mesoplodon ginkgodens, which is named for its tusk-like teeth.

"Now it turns out that Deraniyagala was right regarding the uniqueness of the whale he identified. While it is closely related to the ginkgo-toothed beaked whale, it is definitely not the same species," said Dalebout.

He and colleagues used a combination of DNA analyses and physical characteristics to identify the new species from seven specimens that were discovered in Sri Lanka, the Gilbert Islands (now Kiribati), Palmyra Atoll in the Northern Line Islands near Hawai'i, the Maldives, and the Seychelles.

Researchers obtained good quality DNA from tissue samples from only one specimen, while they used the other specimens to drill into the bones to analyze short fragments of “ancient DNA.” The team studied all other known beaked whale species to confirm the distinction of Mesoplodon hotaula, including six specimens of the closely related gingko-toothed beaked whale.

"A number of species in this group are known from only a handful of animals, and we are still finding new ones, so the situation with Deraniyagala's whale is not that unusual," Dalebout explained. "For example, the ginkgo-toothed beaked whale, first described in 1963, is only known from about 30 strandings and has never been seen alive at sea with any certainty. It's always incredible to me to realise how little we really do know about life in the oceans. There's so much out there to discover. "

This is not the only new beaked whale species that has come to light recently. In 2002 researchers discovered the Mesoplodon perrini beaked whale species in the North Pacific, and a year later they found the Mesoplodon traversii species in the Southern Ocean. In all, scientists recognize 22 species of beaked whales to date.